Pigments, ascorbic acid, and total polyphenols content and antioxidant capacities of beet (Beta vulgaris) microgreens during growth

Figures & data

Table 1. Changes in the contents of pigments in beet microgreens during different days of growth.^a

Days of growth →	9	12	15	18	21	HSD threshold
Parameters ↓
CHL a	90.10 ± 4.41 c	247.81 ± 9.45 b	362.71 ± 13.58 a	355.72 ± 13.41 a	345.98 ± 13.13 a	19.15
CHL b	36.37 ± 1.37 c	102.54 ± 3.97 b	153.47 ± 6.00 a	152.01 ± 5.01 a	149.16 ± 5.51 a	8.20
Total CHLs	126.46 ± 4.76 c	350.35 ± 13.41 b	516.18 ± 19.52 a	507.73 ± 19.12 a	495.14 ± 18.59 a	27.29
CHL a/b	2.48 ± 0.02 a	2.42 ± 0.01 b	2.36 ± 0.02 c	2.34 ± 0.01 d	2.31 ± 0.02 d	0.02
Total CARs	50.07 ± 2.18 c	89.97 ± 3.24 b	114.00 ± 3.96 a	111.51 ± 3.86 a	108.51 ± 3.76 a	5.87
CHL/ CAR	2.53 ± 0.06 c	3.86 ± 0.04 b	4.53 ± 0.05 a	4.55 ± 0.06 a	4.56 ± 0.04 a	0.05
Betaxanthins	248.48 ± 5.62 d	357.47 ± 8.25 b	422.99 ± 9.63 a	369.53 ± 8.46 b	334.43 ± 8.01 c	14.48
Betacyanins	511.15 ± 12.43 d	727.10 ± 16.31 b	841.85 ± 19.61 a	717.76 ± 16.57 b	627.10 ± 14.23 c	27.46
Total betalains	759.62 ± 17.92 d	1084.57 ± 24.47 b	1264.83 ± 21.69 a	1087.29 ± 24.72 b	961.53 ± 21.55 c	40.66
Betacyanin/ betaxanthin	2.06 ± 0.02 a	2.03 ± 0.01 a	1.99 ± 0.02 b	1.94 ± 0.02 c	1.87 ± 0.02 d	0.03
Total betalians/ CHLs	6.01 ± 0.10 a	3.10 ± 0.05 b	2.45 ± 0.04 c	2.14 ± 0.03 d	1.94 ± 0.03 e	0.10
Total betalains/ CARs	15.18 ± 0.35 a	12.10 ± 0.35 b	11.10 ± 0.15 c	9.75 ± 0.13 d	8.86 ± 0.13 e	0.35

^aAll contents are expressed as mg/100 g dry matter. The means ± SD are calculated from six samples collected in two blocks and three replicates per block. Different letters in a row indicate a statistical difference among the sample means (p < 0.05). CHL: chlorophyll, CAR: carotenoids.

Figure 1. Beet microgreens attributes on dry matter (DM) basis on different days of growth. (a) ascorbic acid content, (b) total polyphenols content as gallic acid equivalent (GAE), (c) antioxidant activity via DPPH assay as ascorbic acid equivalent antioxidant capacity (AEAC), (d) antioxidant activity via FRAP assay as AEAC. Data are expressed as the mean ± SD (block = 2, n = 2 × *3). Different lowercase alphabets indicate significant differences (p < 0.05) among samples within the category

Table 2. Multivariate correlation coefficients among pigments, ascorbic acid, total polyphenols, and antioxidant capacity in beet microgreens during different days of growth.^a

	Total CHLs	Total CARs	Betaxanthin	Betacyanin	Total betalains	Ascorbic acid	Total polyphenols	DPPH assay	FRAP assay
Total CHLs	1.0000
Total CARs	0.9967	1.0000
Betaxanthin	0.8690	0.8932	1.0000
Bbetacyanin	0.7641	0.7972	0.9817	1.0000
Total betalains	0.8032	0.8334	0.9920	0.9979	1.0000
Ascorbic acid	0.9332	0.9525	0.9809	0.9353	0.9548	1.0000
Total polyphenols	0.8635	0.8890	0.9944	0.9785	0.9880	0.9814	1.0000
DPPH assay	0.7707	0.7894	0.9559	0.9621	0.9639	0.9063	0.9580	1.0000
FRAP assay	0.8824	0.8911	0.9608	0.9270	0.9424	0.9470	0.9617	0.9744	1.0000

^aCorrelations were estimated by the row-wise method. CHL: chlorophyll, CAR: carotenoids.

Table 3. Regression coefficients for total chlorophylls, total carotenoids, ascorbic acid, total polyphenols, and antioxidant capacities of beet microgreens as the function of betaxanthins (BX) and betacyanins (BC).^a

Parameters	Constant	a	b	c	d	e
Total chlorophyll	−127.500	8.61775	−3.5476	−0.18571	−0.0391	0.16981
Total carotenoids	−16.563	1.169	−0.42582	0	−0.0002	0
Ascorbic acid	231.475	3.41788	−0.6792	0	−0.00075	0
Total polyphenols	343.616	1.33738	0	0	0	0
DPPH assay	−25.036	0.23538	−0.03206	−0.00947	−0.00276	0.01053
FRAP assay	−20.096	0.45751	−0.14423	−0.01642	−0.00444	0.01729

^aa, b, c, d, and e are coefficients for the term BX, BC, (BX − 347.374)², (BC − 686.494)², and (BX − 347.374) × (BC-686.494), respectively.